Messages in this thread Patch in this message | | | From | Thomas Weißschuh <> | Date | Thu, 03 Aug 2023 09:28:56 +0200 | Subject | [PATCH v3 12/14] selftests/nolibc: prevent out of bounds access in expect_vfprintf |
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If read() fails and returns -1 (or returns garbage for some other reason) buf would be accessed out of bounds. Only use the return value of read() after it has been validated.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- tools/testing/selftests/nolibc/nolibc-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 63f09800057d..0145a44af990 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1055,7 +1055,6 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm lseek(fd, 0, SEEK_SET); r = read(fd, buf, sizeof(buf) - 1); - buf[r] = '\0'; fclose(memfile); @@ -1065,6 +1064,7 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm return 1; } + buf[r] = '\0'; llen += printf(" \"%s\" = \"%s\"", expected, buf); ret = strncmp(expected, buf, c); -- 2.41.0
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